Steam cooking of shellfish is an art long practiced. However, the cooked shellfish has a relatively short shelf life even when maintained at temperatures unfavorable to the growth of bacteria and retardant of decay. Such cooked shellfish typically have a shelf life of less than a week, freezing of the cooked product after cooking or after a week of refrigerated storage resulting in a product of markedly reduced quality. Further, shellfish such as crabs, shrimp, and lobster which are steam-cooked prior to removal of the skeletal portions either by hand or by mechanical means invariably are difficult to separate from the skeletal portions due to the tendency of the edible portion thereof to adhere to the skeletal portions. In particular, mechanical removal techniques employing vacuum-induced meat removal forces are often relatively ineffective when processing shellfish cooked by prior art methods due to the adherence of the edible portions of the cooked shellfish to the skeletal portions and the non-contactive nature of such vacuum removal techniques.
Harris, in U.S. Pat. No. 2,155,308, provides a good example of prior art shellfish cooking methodology wherein steam under pressure is used to cook shrimp, crabs and the like. Virtually every shellfish processing plant in the world utilizes at least a variation on the theme described by Harris; although it is to be noted that the general process of cooking shellfish with pressurized steam was not new with Harris. Harris does not teach subjection of steamed shellfish to a vacuum for any purpose. Lapeyre, in U.S. Pat. No. 2,978,334, generally describes a process for extracting edible portions of crustaceans from skeletal portions thereof. Lapeyre subjects cooked shellfish to a vacuum after freezing the shellfish, the vacuum being intended to explode the frozen shellfish in order that the edible portions can be manually removed from skeletal portions with a certain degree of increased facility. Lapeyre does not indicate the degree of vacuum required to cause such an explosion nor does he indicate that moisture is withdrawn from the shellfish during the "explosion" step. Lapeyre further indicates that the frozen cooked shellfish can be "exploded" by subjection of the shellfish to high pressure, "explosion" occurring on release either of the high pressure or of the vacuum.
The present invention provides an improved steam cooking method for shellfish wherein the cooked product exhibits a shelf life of greater than three weeks when maintained under refrigeration and which can be frozen after such period with substantial retention of desirable qualities. The present method acts to remove moisture from the entrails and body portions of the shellfish, thereby to "dry" the shellfish relative to other cooking processes and thus render the cooked product less subject to bacterial growth during the shelf life thereof. The present method further causes the edible portions of the shellfish to shrink to a degree which reduces adherence thereof to the skeletal portions thereby enabling more rapid and facile removal of said edible portions, especially when vacuum removal techniques are employed.
The invention further provides a method for preparing for cooking and cooking crabs known in commerce as red crabs, these crabs being found primarily in deep water along the Atlantic shelf at least from Maryland northward to Nova Scotia. Essentially, the red crab is pierced, such as through the mouth area, and the stomach and as much of the entrails as possible are removed such as by suction, the eviscerated crabs are then preferably placed in a cooking retort in a position such that drainage from the pierced area can occur during cooking. The crabs are then cooked according to the basic teachings of the invention.
Accordingly, it is an object of the invention to provide a method for steam cooking shellfish to increase the shelf life of the cooked product and to facilitate removal of the cooked edible portions of the shellfish from the skeletal portions thereof.
Further objects and advantages of the invention will become more readily apparent in light of the following detailed description of the preferred embodiments of the invention.